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Commit 92545464 authored by Jeff Davidson's avatar Jeff Davidson
Browse files

Linger the carrier service binding when privileges drop. 

If, when rebinding, no app has carrier privileges, but a binding is
active, instead of immediately unbinding, we schedule an unbind in 30
seconds. During that time period, if any other app comes up with
carrier privileges, the scheduled task is cancelled and the binding is
immediately dropped. If the same app and component regains carrier
privileges, the scheduled task is canceled and the binding left alive.

This keeps the binding alive through temporary blips in carrier
privileges. Note that apart from foreground status, the binding itself
profers no additional privileges or abilities onto the bound
application.

Bug: 33057511
Test: Remove/reinsert SIM before/after 30 seconds, disabling carrier
app entirely.
Change-Id: Ice194fe6ce58f1372369b1799d4d20bd5304f684
parent 81448602

src/java/com/android/internal/telephony/CarrierServiceBindHelper.java

+65 −13
Original line number Diff line number Diff line
@@ -28,6 +28,8 @@ import android.os.Bundle; 
import android.os.Handler;

import android.os.IBinder;

import android.os.Message;

import android.os.Process;

import android.os.SystemClock;

import android.os.UserHandle;

import android.service.carrier.CarrierService;

import android.telephony.SubscriptionManager;
@@ -48,6 +50,12 @@ import java.util.List; 
public class CarrierServiceBindHelper {

    private static final String LOG_TAG = "CarrierSvcBindHelper";



    /**

     * How long to linger a binding after an app loses carrier privileges, as long as no new

     * binding comes in to take its place.

     */

    private static final int UNBIND_DELAY_MILLIS = 30 * 1000; // 30 seconds



    private Context mContext;

    private AppBinding[] mBindings;

    private String[] mLastSimState;
@@ -70,6 +78,7 @@ public class CarrierServiceBindHelper { 
    };



    private static final int EVENT_REBIND = 0;

    private static final int EVENT_PERFORM_IMMEDIATE_UNBIND = 1;



    private Handler mHandler = new Handler() {

        @Override
@@ -83,6 +92,10 @@ public class CarrierServiceBindHelper { 
                    log("Rebinding if necessary for phoneId: " + binding.getPhoneId());

                    binding.rebind();

                    break;

                case EVENT_PERFORM_IMMEDIATE_UNBIND:

                    binding = (AppBinding) msg.obj;

                    binding.performImmediateUnbind();

                    break;

            }

        }

    };
@@ -129,6 +142,7 @@ public class CarrierServiceBindHelper { 
        private long lastUnbindMillis;

        private String carrierPackage;

        private String carrierServiceClass;

        private long mUnbindScheduledUptimeMillis = -1;



        public AppBinding(int phoneId) {

            this.phoneId = phoneId;
@@ -158,15 +172,16 @@ public class CarrierServiceBindHelper { 


            if (carrierPackageNames == null || carrierPackageNames.size() <= 0) {

                log("No carrier app for: " + phoneId);

                unbind();

                // Unbind after a delay in case this is a temporary blip in carrier privileges.

                unbind(false /* immediate */);

                return;

            }



            log("Found carrier app: " + carrierPackageNames);

            String candidateCarrierPackage = carrierPackageNames.get(0);

            // If we are binding to a different package, unbind from the current one.

            // If we are binding to a different package, unbind immediately from the current one.

            if (!TextUtils.equals(carrierPackage, candidateCarrierPackage)) {

                unbind();

                unbind(true /* immediate */);

            }



            // Look up the carrier service
@@ -187,15 +202,17 @@ public class CarrierServiceBindHelper { 
            if (metadata == null ||

                !metadata.getBoolean("android.service.carrier.LONG_LIVED_BINDING", false)) {

                log("Carrier app does not want a long lived binding");

                unbind();

                unbind(true /* immediate */);

                return;

            }



            if (!TextUtils.equals(carrierServiceClass, candidateServiceClass)) {

                // Unbind if the carrier service component has changed.

                unbind();

                // Unbind immediately if the carrier service component has changed.

                unbind(true /* immediate */);

            } else if (connection != null) {

                // Component is unchanged and connection is up - do nothing.

                // Component is unchanged and connection is up - do nothing, but cancel any

                // scheduled unbinds.

                cancelScheduledUnbind();

                return;

            }
@@ -212,8 +229,9 @@ public class CarrierServiceBindHelper { 


            String error;

            try {

                if (mContext.bindService(carrierService, connection, Context.BIND_AUTO_CREATE |

                            Context.BIND_FOREGROUND_SERVICE)) {

                if (mContext.bindServiceAsUser(carrierService, connection,

                        Context.BIND_AUTO_CREATE |  Context.BIND_FOREGROUND_SERVICE,

                        mHandler, Process.myUserHandle())) {

                    return;

                }
@@ -224,19 +242,46 @@ public class CarrierServiceBindHelper { 


            log("Unable to bind to " + carrierPackage + " for phone " + phoneId +

                ". Error: " + error);

            unbind();

            unbind(true /* immediate */);

        }



        void unbind() {

        /**

         * Release the binding.

         *

         * @param immediate whether the binding should be released immediately or after a short

         *                  delay. This should be true unless the reason for the unbind is that no

         *                  app has carrier privileges, in which case it is useful to delay

         *                  unbinding in case this is a temporary SIM blip.

         */

        void unbind(boolean immediate) {

            if (connection == null) {

                // Already fully unbound.

                return;

            }



            // Only let the binding linger if a delayed unbind is requested *and* the connection is

            // currently active. If the connection is down, unbind immediately as the app is likely

            // not running anyway and it may be a permanent disconnection (e.g. the app was

            // disabled).

            if (immediate || !connection.connected) {

                cancelScheduledUnbind();

                performImmediateUnbind();

            } else if (mUnbindScheduledUptimeMillis == -1) {

                long currentUptimeMillis = SystemClock.uptimeMillis();

                mUnbindScheduledUptimeMillis = currentUptimeMillis + UNBIND_DELAY_MILLIS;

                log("Scheduling unbind in " + UNBIND_DELAY_MILLIS + " millis");

                mHandler.sendMessageAtTime(

                        mHandler.obtainMessage(EVENT_PERFORM_IMMEDIATE_UNBIND, this),

                        mUnbindScheduledUptimeMillis);

            }

        }



        private void performImmediateUnbind() {

            // Log debug information

            unbindCount++;

            lastUnbindMillis = System.currentTimeMillis();



            // Clear package state now that no binding is present.

            // Clear package state now that no binding is desired.

            carrierPackage = null;

            carrierServiceClass = null;
@@ -244,6 +289,12 @@ public class CarrierServiceBindHelper { 
            log("Unbinding from carrier app");

            mContext.unbindService(connection);

            connection = null;

            mUnbindScheduledUptimeMillis = -1;

        }



        private void cancelScheduledUnbind() {

            mHandler.removeMessages(EVENT_PERFORM_IMMEDIATE_UNBIND);

            mUnbindScheduledUptimeMillis = -1;

        }



        public void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
@@ -253,6 +304,7 @@ public class CarrierServiceBindHelper { 
            pw.println("  lastBindStartMillis: " + lastBindStartMillis);

            pw.println("  unbindCount: " + unbindCount);

            pw.println("  lastUnbindMillis: " + lastUnbindMillis);

            pw.println("  mUnbindScheduledUptimeMillis: " + mUnbindScheduledUptimeMillis);

            pw.println();

        }

    }
@@ -322,7 +374,7 @@ public class CarrierServiceBindHelper { 
                }

                if (appBindingPackage == null || isBindingForPackage) {

                    if (forceUnbind) {

                        appBinding.unbind();

                        appBinding.unbind(true /* immediate */);

                    }

                    appBinding.rebind();

                }